JP3717769B2 - Folding mobile phone terminal - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a foldable mobile phone terminal in which a plurality of flexible printed circuit boards are spiraled at a hinge portion.
[0002]
[Prior art]
Currently, a foldable mobile phone and a foldable PHS (Personal Handyphone System) are commercially available. This foldable terminal has two rotating bodies, a receiving unit and a transmitting unit, coupled to each other so as to be rotatable by a hinge unit, and a flexible connection for electrically connecting the receiving unit and the transmitting unit within the hinge unit. The printed circuit board passes. The flexible printed circuit board in the hinge portion is wound in a spiral shape to prevent damage such as disconnection due to opening and closing (see JP-A-1-89845).
[0003]
[Problems to be solved by the invention]
However, the number of conductive wires that must be accommodated on the flexible printed circuit board is increasing due to the improvement in the functions of the mobile phone. As a result, the width of the flexible printed circuit board exceeds the allowable width for a foldable terminal.
[0004]
As a method for solving this problem, a method of forming a flexible printed circuit board in multiple layers is conceivable. However, in a multilayer flexible printed circuit board, since a large tension is applied to the outer conductive wire by bending, the durability of opening and closing is lowered compared to one side. .
[0005]
Therefore, it is conceivable that a plurality of single-layer flexible printed circuit boards are passed through the hinge portion, but in this case, since the radius of the spiral is reduced by bending, the friction of the flexible printed circuit board increases. Occurs. FIG. 5 is a side view showing a case where the friction becomes extremely large. By closing the cellular phone terminal, the spiral of the inner and outer flexible printed circuit boards (4) and (5) is reduced. For reasons that will be described later, since the spiral of the outer flexible printed circuit board (5) is smaller than the inner flexible printed circuit board (4), the non-spiral portion (42) (43) of the inner flexible printed circuit board (4). ) Is compressed as it is deformed. Then, the friction force of the spiral part of both flexible printed circuit boards (4) and (5) becomes extremely large by the reaction force.
[0006]
[Means for Solving the Problems]
The foldable mobile phone terminal according to the present invention includes first and second casings that are openable and closable via a hinge, and the first casing to the second casing via the hinge. A plurality of flexible printed circuit boards disposed within the hinge portion, wherein the plurality of flexible circuit boards are disposed in a spiral shape and are closed when the first and second housings are closed. The average radius of the inner surface of the flexible printed circuit board is larger than the average radius of the outer surface of the inner flexible printed circuit board by a predetermined dimension or more.
[0007]
The foldable mobile phone terminal according to claim 2 is the foldable mobile phone terminal according to claim 1, wherein a clearance between spiral portions of the outer flexible printed circuit board and the inner flexible printed circuit board is 0. 0. It is 5 mm or more.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The form of the Example of this invention is demonstrated based on figures. FIG. 1 is a partially transparent perspective view showing a state before the flexible printed circuit board (1) is assembled into the casing of the mobile phone terminal, and FIG. 2 is a partially transparent perspective view showing the state after being assembled.
[0009]
The cellular phone terminal of the present embodiment is a foldable type including a receiver (1), a transmitter (2), and a hinge (3).
[0010]
The printed circuit board (11) of the receiver unit (1) and the printed circuit board (21) of the transmitter unit (2) are electrically connected by the first and second flexible printed circuit boards (4) and (5) that are stacked one above the other. The This connection is made by connectors (12), (13), (22), and (23) with a lock mechanism, so that the connection of the first and second flexible printed boards (4) and (5) is not easily disconnected. .
[0011]
The casing (14) of the receiver unit (1) and the casing (24) of the transmitter unit (2) are rotatably connected by a hinge unit (3), and the receiver unit (1) and the transmitter unit (2) ) Opens and closes at an angle of α radians.
[0012]
When the receiver (1) connected by the first and second flexible printed boards (4) and (5) and the printed boards (11) and (12) of the transmitter (2) are incorporated in the mobile phone terminal, 1. The part corresponding to the hinge part (3) of the second flexible printed circuit board (4) (5) is wound once in the rotation direction of the hinge part (3).
[0013]
3 and 4 are side views showing changes in the helical state of the first and second flexible printed boards (4) and (5). FIG. 3 shows a state in which the mobile phone terminal is opened, and FIG. 4 shows a state in which it is closed.
[0014]
In the opened state in FIG. 3, the average radius R1 of the outer surface (41) of the first flexible printed circuit board (4) which is the inner side is the inner surface (51) of the second flexible printed circuit board (5) which is the outer side. It is slightly larger than the average radius R2.
[0015]
Here, how the gap of the spiral portion changes by closing will be described. First, the spiral change of the first flexible printed circuit board (4) due to closing will be described. The average radius of the outer surface (41) of the closed first flexible printed circuit board (4) is R1 ′, and the first flexible printed circuit board (4) on the non-spiral receiving unit (1) side and transmitting side (2) ) Are respectively L1 and L2 (see FIG. 4). The closing angle is α radians, and the spiral shape is approximately circular.
[0016]
The length between the connectors (12) and (22) of the first flexible printed circuit board (4) in the opened state (FIG. 3) is L1 + L2 + 2πR1 + (π−α) R1. Here, (π−α) R1 is a portion where the spirals overlap. The length between the connectors (12) and (22) of the first flexible printed circuit board (4) in the closed state (FIG. 4) is L1 + L2 + 2πR1 ′ + πR1 ′. Here, πR1 ′ is a portion where the spirals overlap. Since the length in the open state (FIG. 3) and the length in the closed state (FIG. 4) are the same, L1 + L2 + 2πR1 + (π−α) R1 = L1 + L2 + 2πR1 ′ + πR1 ′. When this is solved, R1 ′ = R1−αR1 / 3π. That is, when the hinge part (3) is closed by α radians, the radius of the spiral of the first flexible printed circuit board (4) is shortened by αR1 / 3π.
[0017]
Similarly, the spiral radius of the second flexible printed circuit board (5) is shortened by αR2 / 3π when the hinge portion (3) is closed by α radians.
[0018]
Here, since R2> R1, αR2 / 3π> αR1 / 3π is satisfied, and the outer surface (41) of the first flexible printed circuit board (4) which is the inner side and the second flexible printed circuit board (5) which is the outer side. The gap between the inner surfaces (51) of the first and second flexible printed circuit boards (ie, the gap between the upper and lower flexible printed circuit boards) is narrowed by closing the hinge portion (3).
[0019]
Therefore, it is designed so that a gap is formed in the spiral portions of the upper and lower flexible printed circuit boards (4) and (5) in the closed state of FIG. 4 instead of the opened state of FIG. According to experiments, when a gap having an average radius of 0.2 mm was provided, there was no disconnection of the flexible printed circuit board even after opening and closing 100,000 times. In the experiment, a gap of 0.2 mm or more is necessary, but considering the relative displacement of the centers of the spirals and variations in part dimensions, etc., in actual mass production, allow a margin of 0.5 mm or more. It is preferable to do.
[0020]
In the above calculation, the spiral shape is regarded as a circle. However, when designing for mass production, it is sufficient to check the gap with a handmade product. Moreover, the clearance gap is given a clearance in consideration of the relative shift of the centers of the plurality of spirals.
[0021]
In addition, although the overlap of the flexible printed circuit board of the above-mentioned Example was two sheets, this invention can be easily applied also to the case of three or more sheets.
[0022]
【The invention's effect】
As described above, in the cellular phone terminal in which a plurality of flexible printed boards overlap and spiral in the hinge portion, the gap between the upper and lower flexible printed boards is narrowed in this state. Design with a gap. For this reason, friction between flexible printed circuit boards is reduced, and the durability of opening and closing is improved.
[0023]
In addition, in consideration of the relative shift of the centers of the plurality of spirals, a clearance is provided in the closed gap, so that friction is reduced.
[Brief description of the drawings]
FIG. 1 is a partially transparent perspective view showing a state before a flexible printed circuit board is incorporated in a mobile phone terminal.
FIG. 2 is a partially transparent perspective view showing a state after FIG. 2 is assembled.
FIG. 3 is a side view showing a state of the spiral portion in an open state.
FIG. 4 is a side view showing a state of the spiral portion in a closed state.
FIG. 5 is a side view showing a conventional example corresponding to FIG. 4;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Reception part 11 Reception board printed circuit board 12 Reception part connector 13 Reception part connector 14 Reception part case 2 Transmission part 21 Transmission part printed circuit board 22 Transmission part connector 23 Transmission part connector 24 Reception Housing 3 of the hinge part 4 First flexible printed circuit board 41 Upper surface of the first flexible printed circuit board 5 Second flexible printed circuit board 51 Upper surface of the second flexible printed circuit board

Claims (2)

First and second housings that are openable and closable via hinges, and a plurality of flexible printed circuit boards that are arranged from the first housing to the second housing via hinges Prepared,
In the hinge portion, the plurality of flexible boards are overlapped and arranged in a spiral shape, and when the first and second housings are closed, the average radius of the inner surface of the outer flexible printed board is on the inner side. A foldable mobile phone terminal characterized by being larger than a predetermined dimension by an average radius of an outer surface of a flexible printed circuit board. 2. The foldable mobile phone terminal according to claim 1, wherein a gap between spiral portions of the outer flexible printed board and the inner flexible printed board is 0.5 mm or more. Terminal.

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